1. Field of the Invention
This invention relates to devices and techniques for sealing cylindrical members to circumscribing conduits within a well bore. More specifically, the invention relates to a well packer for sealing a pipe string to a surrounding well conduit, such as is provided by the casing or liner, and is suitable for use in corrosive environments.
2. Description of the Prior Art
Well packers and other downhole equipment are often subjected to corrosive environments. One particular problem area is the injection of carbon dioxide during well stimulation techniques. Because carbon dioxide adversely effects the metal parts of the packer, it is advantageous to provide a packer with upper and lower sealing elements which protect the mechanically operated anchoring components from the corrosive environment.
The present invention has as its object the provision of a dual seal well packer which can be both set and released by right hand rotation of the well string leading to the well surface.
Another object of the invention is the provision of such a well packer of simplified design which utilizes rocker type slips which are engaged with the surrounding well casing by a single expander ring to resist axial loading in a first axial direction.
Another object of the invention is the provision of such a well packer which utilizes a slip having a support surface which engages a mating support surface of the slip cage for resisting axial loading in a second axial direction.
Another object is to provide such a device which is set by means of a tension sleeve and dog arrangement which allow the device to be set multiple times and released by right hand rotation from the well surface.
Another object is to provide such a device which can be optionally released by a straight pull on the well string from the well surface.
These and other objects are accomplished as described in the specification which follows: